News about reptiles and amphibians. This may be news from herpetologists, organizations, but also from private persons. Everyone is welcome to send me some news about the protection, abusing, mistreatment, discoveries, etc., of these fascinating animals .

dinsdag 1 mei 2012

24 New Species of Skinks Discovered on Caribbean Islands

24 New Species of Skinks Discovered on Caribbean Islands

A team of biologists from Penn State University has discovered
24 new species of lizards known as skinks, all from islands in the
Caribbean.

The Anguilla Bank skink, one of the 24 new skink species discovered by
Penn State scientists (Karl Questal / Penn State University)

The newly discovered skinks are reported today in a 245-page article in the journal Zootaxa.
About 130 species of reptiles from all over the world are added to
the global species count each year in dozens of scientific articles.
However, not since the 1800s have more than 20 reptile species been
added at one time.
Primarily through examination of museum specimens, the team
identified a total of 39 species of skinks from the Caribbean islands,
including 6 species currently recognized, and another 9 named long ago
but considered invalid until now.
“Now, one of the smallest groups of lizards in this region of the
world has become one of the largest groups,” said Blair Hedges, a
professor of biology at Penn State University and a lead author. “We
were completely surprised to find what amounts to a new fauna, with
co-occurring species and different ecological types. Some of the new
species are 6 times larger in body size than other species in the new
fauna.”
These New World skinks, which arrived in the Americas about 18
million years ago from Africa by floating on mats of vegetation, are
unique among lizards in that they produce a human-like placenta, which
is an organ that directly connects the growing offspring to the maternal
tissues that provide nutrients, Prof. Hedges also explained.
“While there are other lizards that give live birth, only a fraction
of the lizards known as skinks make a placenta and gestate offspring for
up to one year,” Prof. Hedges said. He also speculated that the lengthy
gestational period may have given predators a competitive edge over
skinks, since pregnant females are slower and more vulnerable.
The researchers note that about half of the newly found skinks
already may be extinct or close to extinction. The loss of skink species
can be attributed primarily to predation by the mongoose – an invasive
predatory mammal that was introduced by farmers to control rats in
sugarcane fields during the late nineteenth century.
“The mongoose is the predator we believe is responsible for many of
the species’ close-to-extinction status in the Caribbean,” Prof. Hedges
said. “Our data show that the mongoose, which was introduced from India
in 1872 and spread around the islands over the next three decades, has
nearly exterminated this entire reptile fauna, which had gone largely
unnoticed by scientists and conservationists until now.”
This newly discovered skink fauna will increase dramatically the
number of reptiles categorized as critically endangered by the
International Union for Conservation of Nature in their Red List of
Threatened Species.
“According to our research, all of the skink species found only on
Caribbean islands are threatened,” Prof. Hedges said. “That is, they
should be classified in the Red List as either vulnerable, endangered,
or critically endangered. Finding that all species in a fauna are
threatened is unusual, because only 24 percent of the 3,336 reptile
species listed in the Red List have been classified as threatened with
extinction. Most of the 9,596 named reptile species have yet to be
classified in the Red List.”

Researchers led by Blair Hedges, professor of biology at Penn State University,
attributed their loss to the mongoose, a predatory mammal introduced by
farmers to control rats in sugarcane fields during the late 19th
century.

"The mongoose is the predator we believe is
responsible for many of the species' close-to-extinction status in the
Caribbean," said Hedges, the journal Zootaxa reports.

"Our data show that the mongoose, which was introduced from India in
1872 and spread around the islands over the next three decades, has
nearly exterminated this entire reptile fauna, which had gone largely
unnoticed by scientists and conservationists until now," said Hedges,
according to a Penn statement.

About 130 species of reptiles
are added to the global species count each year in dozens. However, not
since the 1800s have more than 20 reptile species been added at one
time.

Primarily through examination of museum specimens, the
team identified a total of 39 species of skinks from the Caribbean
islands, including six species currently recognized, and another nine
named long ago but considered invalid until now.

"We were
completely surprised to find what amounts to a new fauna, with
co-occurring species and different ecological types," Hedges said. He
added that some of the new species are six times larger in body size
than other species in the new fauna.

Hedges also explained that
these New World skinks, which arrived in the Americas about 18 million
years ago from Africa by floating on mats of vegetation, are unique
among lizards in that they produce a human-like placenta, which is an
organ that directly connects the growing offspring to the maternal
tissues that provide nutrients.

"While there are other lizards
that give live birth, only a fraction of the lizards known as skinks
make a placenta and gestate offspring for up to one year," Hedges said.

He also speculated that the lengthy gestational period may have given
predators a competitive edge over skinks, since pregnant females are
slower and more vulnerable.